The present invention relates to an input device for manually entering information into various systems such as computers, word processors, or facsimile transmitter/receivers.
Various manual information input or entry devices are used in connection with information-related systems such as computers and word processors and communication systems such as facsimile transmitter/receivers for directly entering desired information through a process similar to the writing process of a human hand. Such manual information input devices employ the principles of electromagnetic induction or electrostatic coupling. The conventional manual information input devices are disadvantageous in that they require special input styli such as electromagnetic pens and light pens for the entry of information.
FIG. 8 shows, by way of example, a conventional manual information input device capable of entering desired information through the use of a readily available writing instrument such as a ball-point pen, a pencil, or a fountain pen, rather than a specially designed stylus. The manual information entry device illustrated in FIG. 8 at (I), generally designated at 10, comprises a substrate 12, a resilient input panel 14, a spacer 16, and electrodes 12A, 14A.
The substrate 12 and the input panel 14 support the electrodes 12A, 14A on their one surface and are disposed with the electrodes 12A, 14A confronting each other. The spacer 16 is interposed between the substrate 12 and the input panel 14 for spacing them a given distance apart from each other. The electrodes 12A, 14A are in the form of rectangular stripes. The strip elecrrodes 12A extend parallel to each other, and the stripe electrodes 14A extend parallel to each other, whereas the stripe electrodes 12A, 14A extend perpendicularly to each other. Specifically, the stripe electrodes 12A are directed longitudinally parallel to the sheet of FIG. 8 and spaced at small intervals in a direction normal to the sheet of FIG. 8. The stripe electrodes 14A are directed longitudinally in a direction normal to the sheet of FIG. 8 and spaced at small intervals parallel to the sheet of FIG. 8.
If the images of these stripe electrodes 12A, 14A were projected onto the substrate 12, then their crossing points would be arranged as a two-dimensional matrix referred to as a pixel matrix. Stated otherwise, the electrodes 12A, 14A constitute such a pixel matrix. Assuming that the electrodes 12A are successively numbered as 1, 2, . . . , i, . . . , N and the elecrtrodes 14A are also successively numbered as 1, 2, . . . , j, . . . , M, each of the pixels of the pixel matrix can be indicated as (i, j) where i=1 through N, j=1 through M).
In operation, a voltage is applied between the electrodes 12A, 14A. When the input panel 14 is pushed as indicated by the arrow in FIG. 8(II) by a pointed input pen such as a ball-point pen, the input panel 14 is resiliently depressed toward the substrate 12 until a gth stripe electrode 14A, for example, is brought into electric contact with a pth stripe electrode 12A on the substrate 12. The position where the input panel 14 is pushed can be electrically identified as the combination (g, p) of the stripe electrodes thus held in contact with each other. As The input pen is moved to draw a desired pattern to be entered on the input panel 14, the position (g, p) of the pushed position is varied to enter the pattern as an electric signal representative of the time-dependent change of the position (g, p).
However, the above manual input device has the following problem: If a finger or part of a hand accidentally touches the input panel 14 while desired information is being entered, the input panel 14 is resiliently deformed to bring unwanted electrodes into electric contact with each other, resulting in entry of such an accidental touch as erroneous information which acts as noise with respect to the desired information to be entered.